1. Field of the Invention
This invention relates to fabric conditioning products suitable for use at elevated temperatures encountered in laundry dryers. In particular the invention relates to improving a compressing step for eliminating the rigidity imparted to the substrate by the fabric softening agents.
2. Description of the Prior Art
Surface modification of fabrics, particularly cellulosic fabrics, to soften and impart properties such as antistatic, lubricating, bacteriostatic, mildew-proof and moth-proof properties has been accomplished by treating the fabrics with appropriate chemicals for modifying such properties. It is now common practice to treat various types of household apparel and fabrics such as wool, cotton, and synthetics such as polyesters or nylon, with one or more specialized conditioning agents for affecting the softness and other properties of the fabrics.
For various beneficial reasons, the practice has recently developed of softening and otherwise conditioning household apparel and fabrics during drying of the fabrics after laundering. Fabric conditioning products comprising sheet goods (substrate) coated or impregnated with a fabric-softening chemical and/or other specialized fabric conditioning chemicals have been commingled with damp laundry during the drying of the laundry at the elevated temperatures encountered in a typical household laundry dryer. The elevated temperatures encountered during drying releases the specialized fabric conditioning chemicals which are transferred to the commingled fabrics during drying.
Typical absorbent sheet goods employed as a substrate for heat-activated, fabric-softening products include flexible foam, felted, non-woven, air-lay and wet-lay fibrous sheets such as paper toweling, skrims, cloth, and air-lay webs composed of cellulosic or synthetic fibers of papermaking-length or longer. For example see U.S. Pat. No. 3,442,692 entitled METHOD OF CONDITIONING FABRICS.
Fabric-softening chemicals and other specialized chemicals for conditioning fabrics have been coated onto or impregnated into such absorbent substrates. Preferably, to avoid staining and other problems during drying, the conditioning chemicals have been impregnated into the absorbent substrate in combination with controlling the absorbent characteristics of the substrate. For example see U.S. Pat. No. 3,686,025 entitled TEXTILE SOFTENING AGENTS IMPREGNATED INTO ABSORBENT MATERIALS.
The fabric conditioning chemical is applied to the absorbent substrate in liquid form (a molten bath or a solution made with a solvent) and then solidified (by cooling or evaporating the solvent). The absorbent substrate with the solidified fabric conditioner impregnated into the substrate is stiff and boardy due to the solidified fabric conditioner even if the substrate was soft and flexible prior to being impregnated.
Previously it was discovered that temporarily compressing a thick, absorbent substrate having a solidified fabric conditioner chemical impregnated therein produces a softer, more flexible impregnated substrate. The compressing should reduce the thickness of the substrate to less than 70% of its original thickness. The substrate usually returns to substantially its original thickness shortly after the compressive forces are released. The process of compressing such impregnated substrates is disclosed in a U.S. Patent Application entitled IMPROVED FABRIC SOFTENER COMPOSITION, invented by Robert A. Volz and Robert E. Welsh, and assigned to Scott Paper Company, which process is improved by the present invention.